Reactions of sulphate, phosphate and hydroxyl radicals with furan. An electron spin resonance investigation in solution

Abstract

The e.s.r. techniques of in-situ photolysis and in-situ radiolysis have been used to investigate the reactions of sulphate, phosphate and hydroxyl radicals with furan. The phosphate and hydroxyl radicals undergo addition at the 5-position of furan and form the respective adduct radicals. With the sulphate radical, however, the hydroxyl-radical adduct is observed instead of the sulphate-radical adduct. This is explained as being due to the formation of a cation-radical intermediate which reacts with water to form the hydroxyl-radical adduct. The latter undergoes ring opening at near neutral pH, whereas the phosphate-radical adduct is stable even in highly alkaline media.